Method of treating pineapple plants



Patented Nov. 15,1949

Ferdinand P. Mehrlich, Honolulu, Territory of Hawaii, assignor to Hawaiian PineappleConipany, Limited, Honolulu, Territory .ofIHaw'aii, a corporation of Hawaii No Drawing. Original applicationsAprilBO, 1943,

Serial No. 485,181, now Patent-No. 2,428,335, and January 24, 1944, Serial No'. 519,539, now Patent No. 2,441,163. Divided andthis application September 8, 1947, Serial No. 772,899

3 Claims.

This invention relates to the culture of pineapple plants and to methods for chemically controlling the growth thereof. More particularly, the invention. concerns the application to pineapple plants of those synthetic organic compounds known as plant hormones which, under certain conditions of application, have a general growth stimulating efiect on plants. As example of such synthetic plant hormones may be mentioned naphthalene and indole compounds 1 such as alpha naphthaleneacetic, beta naphthoxy acetic, indoleacetic and 'indolebutyric acids, and amides and alkali metal salts thereof.

An object of the invention is to provide novel methods of pineapple culture in which, b the utilization of such compounds, the size and weight of the pineapple fruit are substantially increased and its quality is improved. Another object is to provide such a method by which the time of differentiation and flowering and/or the date of maturation of the fruit may be changed as desired. As is well known, differentiation is the change of the plant from vegetative to flowering condition.

This application is a division of myco-pending applications, Ser. No. 485,181, filed April '30, 1943, now Patent No. 2,428,335, in which treatment after difierentiation of the plants is claimed, and Ser. No. 519,539, filed January 24,1944, now Patent No. 2,441,163, in which pre-difierentiation treatment of the plants with hormone-liquid carrier mixtures to delay differentiation is claimed.

In conventional pineapple culture, considerable difficulty may be experienced by the Weakening of the peduncle (fruit stem) allowing the fruit to fall over, exposing large areas of the fruit. to the direct rays of the sun. This resultsin considerable damage to the fruit and loss in recovery from sun-scald or sunburn of the fruit.

A further object of the invention is to pro-- vide a novel method for pineapple culture in which, through the use of synthetic hormones, the pineapple stem (peduncle) is strengthened, the fruit is kept erect, sun-scald is reducethand the size and weight of the fruit are increased.

Another object of the invention is to effect. a mechanical strengthening of the outer tissues of the fruit which are commonly referredto asthe shell of the fruit. It is desirable to strengthen these tissues as a means of limiting bruisin of the fruit in the harvesting operationsand in the transportation and other handling of the fruit.

I have made the important discovery that the beneficial results which it is the object ofthis invention to produce can be obtained by application of synthetic hormones directly to the growing plant at propertimes and in proper concentrations and. quantities as will be hereinafter fully explained. By means of this discov ry, I am enabled tobring ab ut an increase in the weight of thepineapple Iruit by as much as a pound or more per fruit while also correspondin ly nc easing its size and imp o ing. it q a ty. This amounts t an increase of ei h tons or more fruitper-acre. I also accomplisha elay i hematuration of th pine p -crop of as much as two mont s; n advan o del y, as desired, in the-time of difierentiation and flow r n ye matter of weeks; a a st en ening of the peduncle.

In establishing the -ioregoing, numerous tests have been conducted 01 many plants and in different fields, the efiects being checked by comparison; with untreated plants in the same 10- cality.

In an illustrativeset of these tests, which will serve to illustrate the process as applied to the improvement of the fruit and peduncle, the plants treated had inall cases differentiated and Were in various stages of development between difierentiationand maturity of the fruit. The plant hormones employed were alpha naphthaleneacetic acid, potassium naphthalene acetate and alpha n-aphthylacetamide. The hortmone was mixed in a liquid carrier consisting of water or of water and lanolin emulsion which was sprayed or poured over the hearts and leaves of'the plants in .approximatelythe quantity of 25 cc. to cc. of mix to'each plant. The .concentrations of mix used were, in proportions of parts ofrhormone to parts of carrier1z500, 11:1,,000, 1:5,000, 110,000, 1120,000, 1:33,.500. V

In all cases except where the fruit was substantially fully grown at the time of treatment, the following, efiects were produced;

1. Maturation and ripening of the fruit were delayed, from one week to two months, generallyirom twoto three weeks.

2. The weight and size of the fruit were increased, thefruit of. the treated plantsbeing frequently more than a pound heavier than the fruit of thejeomnarative untreatedplants.

v.3. ,Thequality ,of the rfruitwasiimproved.

4. The fruit of .thetreated plants had. larger, morerobusteyes than the fruit of the comparatrveuntreated plants,

5. The peduncles of. the treated plants were larger, stronger .andmore fibrous. than those of the com arative untreated plants.

.In the cases where the ,truitWas' full grown ,at the time of treatment no significant effectswere observed.

Th'e'efiects were greatest and approximately the same with the hormone concentrations of from 1,000to 3.3.5 0 pa t oarrier to one part of. hormo e appl ed at any s a of plant d elopment between differentiation and half wth o theiruiti. v V l Tests have shown that the effectiveness of a dry dusting powder mix for purposes of the present invention is about one-tenth that of the liquid mix at the same concentrations so that, if such a mix is employed, it should have about ten times the proportion of hormoneto carrier of the liquid mixture.

Successive applications at spaced intervals sufficiently long to insure complete absorption by the plant of the hormone from the previous application, such as the intervals of last flower, onequarter grown fruit, one-half grown fruit, etc., produced the same effects but to an enhanced degree as compared with the single application of corresponding hormone concentration. Successive applications at spaced intervals of only a few days produced the same effects but to an enhanced degree. Applications should be particularly directed onto the forming fruit.

I have also found that by applying synthetic hormones to the pineapple plants in advance of the normal date of differentiation, their difierentiation and flowering may be retarded or advanced as desired according to the concentration of hormone employed, and the maturation date of the ensuing crop will be correspondingly retarded or advanced, provided hormone treatments are not applied during or after difierentiation.

Thus, by applying synthetic hormones to the pineapple plants only in advance of differentiation in concentrations of one part hormone to from 1,000 to 10,000 parts of liquid carrier I have substantially delayed differentiation and flowering of the plants and also, correspondingly, maturation of the ensuing crop; whereas, if the hormones are applied to the plants in lesser concentrations of one part hormone to from 16,500 to 200,000 parts of carrier, the opposite effects of precocious differentiation, flowering and corresponding advance of the date of crop maturation are produced. For the same effects, the concentrations of dry mixes should be about ten times that indicated for the liquid mixes. The mix is sprayed, poured or dusted onto the hearts and leaves of the plants. Suitable quantities are 25 cc. to 100 cc. liquid mix per plant.

Acceleration or retardation may be produced in this manner, varying from a few days to a matter of weeks, depending on how far in advance of the normal difierentiation date the treatment is given. Within the concentration ranges mentioned, the higher concentrations produce more extensive changes than the weaker concentrations, though repeated applications of a weaker concentration mix may be employed to produce the same result as a single application in greater concentration.

This treatment has no substantial effect on the size and weight of the fruit or on its peduncle structure, merely changing its maturation date. For purposes of delaying crop maturation, therefore, the post-differentiation treatment previously described is more advantageous. However, by advancing the crop maturation date of some only of the plants by such pre-difierentiation treatment, the grower may attain a definite prolongation of his harvesting periods and reduction of peak loads, particularly if he also delays maturation ofsome only of his plants either by postdifferentiation or pre-differentation treatment as previously described. Also, pre-difierentiation treatment which accelerates differentiation may be employed to offset in whole or in part a delay in crop maturation resulting from post-differentiation treatment of the same plants; and, con- Versely, if the plants are given a ire-differentiation treatment which retards their differentiation and are then given the post-differentiation treatment, the delay of their crop maturation date beyond the normal date is greater than that which would result from either treatment alone.

The hormone treatments may be applied to pineapple plants after the first crop; that is, the ratoon crop stage, as well as before the first crop, with like benefits. The fruit bearing suckers of plants in the ratoon stage generally develop unequally, some being much further matured than others at any given time. Such plants may be treated with hormone, in concentrations previously mentioned as suitable for post-difierentiation treatment to increase crop size, at a time when some of the suckers have passed the differentiation stage and others have not. This treatment will produce different effects on individual suckers according to their stage of development, delaying maturation and improving the crop of the suckers which have passed differentiation and, as these concentrations are within the range of concentrations suitable for producing precocious diiferentiation, accelerating differentiation of the other suckers.

In the practice of the invention, I prefer to apply the hormone in a liquid carrier which may suitably be water or a water and lanolin or a water and oil emulsion or a solvent such as alcohol or the like. If a dry powder is used as a carrier, talc, clay, bentonite, kaolin and the like are suitable. The mixture is sprayed, poured or dusted on the plants, care being taken to insure direction of a substantial quantity into the hearts of the plants. Beta naphthoxy acetic acid, alpha naphthaleneacetic acid and alpha naphthylacetamide are considered preferred hormones for purposes of the invention because they are eflicient and comparatively inexpensive and easily obtainable, but other hormones may, of course, be used with like effect as previously noted. A single hormone may be used, or several may be used in combination.

Having now described and explained preferred practice of the invention, what I desire to claim and secure by Letters Patent is:

1. A method for producing delayed differentiation of pineapple plants which comprises applying to the hearts and leaves of the plants prior to differentiation a mixture of a plant hormone and a powdered carrier medium therefor, the hormone concentration of said mixture being in excess of one part of hormone to 1,000 parts of powdered medium.

2. A method for producing delayed differentiation of pineapple plants which comprises applying to the hearts and leaves of the plants prior to differentiation a mixture of a plant hormone and a powdered carrier medium therefor, the hormone concentration of said mixtur being in excess of 1 part of hormone to 1,000 parts of powdered medium, said hormone being selected from the group consisting of alpha naphthaleneacetic, beta naphthoxy acetic, indoleacetic indindolebutyric acids, and amides and alkali metal salts thereof.

3. A method for producing delayed differentiation of pineapple plants which comprises applying to the plants prior to differentiation a mixture of a plant hormone and a powdered carrier medium therefor, the hormone concentration of said mixture being 1 part of hormone to from to 1,000 parts of powdered medium.

FERDINAND P. MEHRLICH.

No references cited. 

